1. Field of the Invention
The present invention relates to a method for accelerating the percutaneous absorption of a physiologically active agent (hereafter often merely an "active agent" for brevity).
2. Description of the Prior Art
Active agents are commonly administered to the skin or mucosal tissues to treat local problems and systemic administration of active agents is commonly accomplished by ingesting pills or by injections. However, recently attempts have been made to achieve systemic administration of active agents by topical applications to the skin or mucosal tissues. Such topical means of achieving systemic administration has the advantage that desired blood levels can be readily achieved and maintained so that duration of therapy can be readily controlled. Thus, side effects due to an overdose of the active agent can be prevented. Also, metabolism due to a first pass through the liver and gastric disturbances, which are characteristic of certain drugs such as indomethacin when administered orally, can also be eliminated.
However, normal skin is relatively impermeable to most therapeutic agents in that desired blood levels of the therapeutic agent cannot be achieved by means of percutaneous absorption. The percutaneous absorption of therapeutic agents can, however, be enhanced by means of adjuvants or penetration enhancers.
One of the best known of such penetrating adjuvants is dimethyl sulfoxide, the use of which is described in detail in U.S. Pat. No. 3,551,554 Herschler et al, which patent broadly suggests the use of dimethyl sulfoxide as a penetrating adjuvant for psychopharmacological drugs such as benzodiazepine derivatives.
British Pat. No. 1,504,302 Brooker et al deals with sedative methods and compositions and discloses the administration of sedatives by applying to the skin of a non-human animal a sedating amount of one or more sedative compounds in various penetrating adjuvants such as hydrocarbons such as aromatic hydrocarbons or paraffins, halogenated aliphatic hydrocarbons, ketones, esters, ethers, alcohols having from two to eight carbon atoms, amides, e.g., dimethyl acetamide, or sulfones. Brooker et al broadly indicates that one or more of the above liquids can be used in combination, but exemplify the halogenated aliphatic hydrocarbons only with carbon tetrachloride and exemplify the amides only with dimethylformamide.
Japanese Patent Application No. 52-148,614 (unexamined) Yonemushi discloses, without supporting data or explanation of substance, the use of sulfones by-produced in the refining of petroleum "as solvents to enhance the efficacy of drugs for skin disease" and "as drug penetration enhancers".
U.S. Pat. No. 4,202,888 Eckert et al discloses absorbable pharmaceutical compositions comprising at least one cardiac glycoside distributed in a vehicle comprising an absorption-enhancing amount of at least a partial glyceride of a fatty acid of medium chain length.
U.S. Pat. No. 3,472,931 Stoughton relates to percutaneous absorption using lower alkyl amides, and exemplifies binary systems which comprise dimethylacetamide and ethanol, dimethylacetamide and isopropyl alcohol and dimethylacetamide and isopropyl palmitate. Stoughton does not exemplify or disclose the combination of dimethylacetamide with higher molecular weight alcohols. At column 5 Stoughton suggests that emollients, including lanolin alcohols and fatty acid alcohols in general, give increased percutaneous absorption and increased retention, resulting in improved softening and moisturizing effects. The main components used in the percutaneous absorption system of Stoughton are amides, including N,N-dimethyl acetamide.
U.S. Pat. No. 3,969,516 Stoughton discloses compositions and methods for the treatment of acne comprising about 0.1 to about 10% by weight of an antibiotic of the lincomycin family. Stoughton lists a substantial number of additional ingredients which can be used in such formulations, including stearyl alcohol, and indicates that preferred ingredients include alcohols and other materials which enhance percutaneous absorption such as 2-pyrrolidone and N-lower alkyl substituted 2-pyrrolidones. In Example V formulations are prepared including, inter alia, N-methyl-2-pyrrolidone and stearyl alcohol. Stearyl alcohol is a C.sub.18 alcohol which is solid at around 37.degree. C.
U.S. Pat. No. 3,989,816 Rajadhyaksha discloses a method for carrying physiologically active agents through body membranes such as skin which comprise an effective, nontoxic amount of certain 1-substituted-azacycloheptan-2-ones. While not exemplified, the formula in Rajadhyaksha is broad enough to include, e.g. methyl caprolactam. Inert carriers may be used in the Rajadhyaksha composition. In Example 3 isopropyl myristate is used, in Example 5 stearyl alcohol is used (a C.sub.18 alcohol having a melting point of 59.degree. C.) and in Examples 8 and 11 cetyl alcohol is used (and C.sub.17 alcohol having a melting point of 49.degree. C.).
U.S. Pat. No. 4,017,641 DiGiulio deals with skin moisturizing compositions comprising 2-pyrrolidones which can be used with suitable oils and waxes including aliphatic straight chain fatty acids and alcohols of from about 10 to about 20 carbon atoms. This patent does not, however, deal with percutaneous administration of physiologically active agents.
European Patent Application No. 0043738 discloses binary percutaneous administration systems which comprise a monoglyceride, a diol or a diol ether in combination with a second component such as an alcohol, ester, amide or the like.
The present invention involves multicomponent carrier systems for the percutaneous administration of physiologically active agents which differ from the systems disclosed in the above prior art.